Peggie Hall wrote:

Don, if you decided to try it, open the deck pumpout fitting VERRRRY
carefully...'cuz if your tank is seriously pressurized, it could produce
a very unpleasant geyser.

Uh yes... That would be... unpleasant. I'll be
careful whatever I do. Right now I have to figure
out where the vent line output is. Any clues on
where to look?

Don W.